What Causes Erectile Dysfunction? Physical, Psychological and Medication Causes

Erectile dysfunction (ED) is the most common sexual health concern men report to their doctor, affecting as many as one in five men in the UK. While it is most frequently associated with older age, ED can occur in men of any age. Understanding the cause is the first and most important step — because the right treatment depends entirely on what is driving the problem. This guide examines the full range of physical, psychological, and medication-related causes of erectile dysfunction.

What Is Erectile Dysfunction?

Erectile dysfunction is characterised by the persistent inability to achieve and/or sustain an erection sufficient for satisfactory sexual intercourse. It is considered a clinical concern when it occurs regularly — occasional difficulties with erections are normal and not a cause for alarm. When ED becomes a consistent pattern, it warrants investigation to identify the underlying cause and determine the most effective treatment. For a broader overview of ED and its treatments, see our guide to understanding and overcoming erectile dysfunction.

Physical Causes of Erectile Dysfunction

At its most fundamental level, ED is caused by disrupted blood flow to the penis. The following conditions can interfere with this:

• Cardiovascular disease — atherosclerosis (hardening of the arteries) reduces blood flow throughout the body, including to the penis
• Diabetes — causes both nerve damage (diabetic neuropathy) and blood vessel damage, both of which impair erectile function
• High blood pressure (hypertension) — damages blood vessel walls over time and reduces penile blood flow
• High cholesterol — contributes to arterial narrowing
• Hormonal conditions — low testosterone (hypogonadism), thyroid disorders (overactive or underactive thyroid), Cushing’s syndrome
• Neurological conditions — Parkinson’s disease, multiple sclerosis, spinal cord injury, epilepsy
• Peyronie’s disease — scar tissue inside the penis causing curved, painful erections
• Obesity — increases cardiovascular risk, affects hormone balance, and impairs blood vessel function
• Sleep apnoea — reduces oxygen delivery and is associated with lower testosterone levels
• Pelvic injury or surgery — particularly prostate surgery; see our guide to whether surgery can cause ED

Psychological Causes of Erectile Dysfunction

Psychological factors are particularly common in younger men experiencing ED. They include:

• Performance anxiety — fear of not being able to achieve or maintain an erection creates a self-fulfilling cycle
• Depression — reduces libido and affects the neurological pathways needed for sexual arousal
• Stress and fatigue — acute or chronic stress (work, financial, relationship) interferes with sexual function
• Relationship problems — communication issues, conflict, or reduced emotional intimacy
• Sexual trauma or past negative experiences
• Excessive pornography consumption — some evidence suggests a connection between high pornography use and performance difficulties with real partners

Medications That Can Cause ED

Several commonly prescribed medications list ED as a known side effect:

If you believe a prescribed medication may be contributing to ED, speak to your prescriber about alternatives — do not stop any medication without medical guidance. For more on lifestyle factors and non-medication approaches, see our guide to lifestyle changes for erectile dysfunction.

When Should You See a Doctor About ED?

• If ED has persisted for more than 2–4 weeks
• If it is causing distress or affecting your relationships or quality of life
• If you have any of the cardiovascular risk factors mentioned above (diabetes, high blood pressure, high cholesterol)
• If ED began after starting a new medication
• If you are under 40 and experiencing ED — a thorough assessment is particularly important in younger men